1. Field of the Invention
This invention relates to a leader tape fixedly attached to a leading end of a tape, such as a magnetic tape for data recording and a cleaning tape for head cleaning, for enabling the tape to be pulled out of a cartridge body, and a tape cartridge incorporating the leader tape.
2. Description of the Related Art
As the tape cartridge of the above-mentioned kind, which incorporates a leader tape, a tape cartridge 31 shown in FIG. 11 has been conventionally proposed. The tape cartridge 31 is a one reel-type recording medium cartridge, and is comprised of a cartridge body 2 having an upper half 2a, a lower half 2b, and a lid 2c, a single reel 3, and a magnetic tape 4 (see FIG. 13) for data recording wound around the reel 3 and accommodated in the cartridge body 2. A leader tape 35 is fixedly attached to the magnetic tape 4, for enabling the tape 4 to be pulled out of the cartridge body 3 by a record/playback device, not shown. As shown in FIGS. 12A, 12B and 13, this leader tape 35 is comprised of a tape body 11 having one end thereof fixedly attached to the magnetic tape 4, a pin 12 attached to the other end of the tape body 11, and engaging hooks 13, 13 fixed to respective opposite ends of the pin 12. As shown in FIG. 15, the tape body 11 has the other end folded such that it surrounds the periphery of the pin 12, and leading end portions 11b of the other end folded are welded to an opposed tape surface of a root portion 11a (see FIG. 13) of the tape body 11 between the one end fixed to the magnetic tape 4 and the folded portion.
In making the leader tape 35, the leading end portions 11b are welded to the root portion 11a by respective horns X11 for ultrasonic welding. More specifically, first, the leading end portions 11b of the tape body 11 are folded such that they surround the periphery of the pin 12, and brought into contact with the root portion 11a. Then, as shown in FIG. 15, the horns X11 each having a prism shape are brought into contact with the respective surfaces of the leading end portions 11b, and ultrasonic waves are delivered from the horns X11 with the leading end portions 11b being urged against the root portion 11a. Each horn X11 has knurls formed on a welding surface (abutment surface via which the horn X11 abuts on the corresponding leading end portion 11b) thereof at a pitch of about 0.6 mm. Therefore, the leading end portions 11b and the root portion 11a are brought into firm contact with each other at the top of each knurl, and are progressively melted and mixed, starting with portions in such a firm contact with each. The portions melted to each other (melted portion) progressively spread until adjacent melted portions overlap each other to cause an area of each leading end portion 11b urged by the corresponding horn X11 and an area at the root portion 11a in contact with the urged area (welded area W11 in FIG. 15) to be entirely welded and mixed to each other. Then, the melted and mixed portions solidify when they cool to normal temperature. This causes each leading end portion 11b and the root portion 11a to be integrated with each other in the respective above-mentioned areas (welded area W11 in FIG. 15), whereby the attachment of the pin 12 to the tape body 11 is completed. In forming the leader tape 35, as described above, the horns X11 having a prism shape are used for welding. Therefore, as shown in FIG. 14, each welded area W11 where each leading end portion 11b and the root portion 11a are welded to each other and a corresponding non-welded portion V11 where the leading end portion 11b and the root portion 11a become apart from each other are divided by a boundary line L11 in the form of a straight line perpendicular to the direction of the length of the tape body 11. Further, the welding surface of the horn X11 has a size which extends beyond an edge E1 of the tape body 11, and hence the leading end portion 11b and the root portion 11a are welded to each other all over the area between the boundary line L11 and the edge E1. This process completes the leader tape 35. After this, the leader tape 35 is fixedly attached to the leading end of the magnetic tape 4, the magnetic tape 4 is wound around the reel 3, and then the resulting assembly is received in the cartridge body 2, whereby the tape cartridge 31 is completed.
However, the conventional leader tape 35 suffers from the following problems: The boundary line L11 dividing between the welded area W11 and the non-welded area V11 is in the form of a straight line perpendicular to the direction of the length of the tape body 11. Therefore, when the pin 12 is pulled via the hooks 13, 13 in a direction indicated by an arrow C1 in FIG. 15 to pull out the magnetic tape 4, stress is concentrated on a portion of the tape body 11 which is very short with respect to the direction of the length of the tape (portion of the boundary line L11). This can cause breakage of the leading end portion 11b along the boundary line L11 or in the vicinity thereof, as shown in FIG. 16.
Further, in the conventional leader tape 35, as shown in FIG. 17A, the leading end portion 11b and the root portion 11a are welded to each other all over the area between the boundary line L11 (not shown in this figure) and the edge E1 to cause the leading end portion 11b and the root portion 11a to be substantially completely integrated with each other in the welded area W11, through solidifying, after being melted to each other, so that the thickness of the tape body 11 (root portion 11a) undergoes a sudden change at the edge E1. Therefore, when the pin 12 is pulled in the direction of an arrow C2 in FIG. 15, stress is also concentrated on the portion of this edge E1. This may cause breakage of the root portion 11a at the edge E1 or in the vicinity thereof, as shown in FIG. 17B.
Further, in the conventional leader tape 35, as shown in FIG. 15, the horns X1 each having a pin 12 side corner thereof scarcely chamfered (e.g. horns X11 each having the corner whose cross-sectional shape is in the form of arc having a radius of 0.1 mm or smaller) are used to effect the welding, and therefore, stress is concentrated on a portion along the boundary line L11. As a result, the residual stress itself of the portion along the boundary line L11 becomes large. This can also cause breakage of the leading portion 11b at the boundary line L11 or in its vicinity, as shown in FIG. 16, when the pulling-out of the magnetic tape 4 is repeatedly carried out. Further, the welding with each horns X1 having the corner thereof scarcely chamfered forms a juncture of the leading end portion 11b between the welded area W11 and the non-welded area V11, in a manner corresponding to the corner of horn X11. Therefore, when the pin 12 is pulled in the direction indicated by the arrow C2 in FIG. 15 to forcibly expand a juncture angle xcex8 formed between the welded area W11 and the non-welded area V11, stress is concentrated at the very narrow boundary line L11, causing breakage at the portion along the boundary line L11.
It is an object of the invention to provide a leader tape which is capable of preventing breakage thereof when a tape is pulled out by the leader tape, and a tape cartridge incorporating the leader tape.
To attain the above object, according to a first aspect of the invention, there is provided a leader tape including a leader tape body having one end fixed to a tape, for enabling the tape to be pulled out of a cartridge body, and a pin member attached to the leader tape body, for pulling out the tape therewith, the leader tape body having a portion thereof on a side of another end opposite to the one end, the portion being folded such that the folded portion surrounds a periphery of the pin member and that the folded portion has a leading end portion thereof welded to a tape surface of the leader tape body opposed to the folded portion, wherein welding is effected non-densely in at least one of a pin member-side boundary portion of a welded area where the folded leading end portion and the tape surface opposed thereto are welded to each other and a one end-side boundary portion of the welded area.
According to this leader tape, at least one of the pin member-side boundary portion of the welded area where the leading end portion and the tape surface opposed thereto are welded to each other and the one end-side boundary portion of the welded area is non-densely welded. Therefore, the force applied to the leader tape body when the leader tape body is pulled can be distributed over the whole of the boundary portion(s), whereby the breakage of the leader tape body due to the pulling force can be fully prevented.
Preferably, in the at least one of the pin member-side boundary portion and the one end-side boundary portion, welded portions are formed in at least one of a polka-dot pattern, a spotted pattern, and a mesh pattern.
To attain the above object, according to a second aspect of the invention, there is provided a leader tape including a leader tape body having one end fixed to a tape, for enabling the tape to be pulled out of a cartridge body, and a pin member attached to the leader tape body, for pulling out the tape therewith, the leader tape body having a portion thereof on a side of another end opposite to the one end, the portion being folded such that the folded portion surrounds a periphery of the pin member and that the folded portion has a leading end portion thereof welded to a tape surface of the leader tape body opposed to the folded portion, wherein welding of the folded leading end portion is effected such that at least one of a pin member-side boundary portion of a welded area where the folded leading end portion and the tape surface opposed thereto are welded to each other and a one end-side boundary portion of the welded area forms an arcuate shape in cross-section along a tape length, the arcuate shape protruding toward the tape surface opposed thereto.
According to this preferred embodiment, welding of the leader tape body is effected such that the pin member-side boundary portion of the folded portion forms an arcuate shape in cross-section along the direction of a tape length, the arcuate shape protruding toward the tape surface opposed thereto. Therefore, even when a juncture angle formed between the welded area of the leading end portion and a non-welded area extending from the welded area toward the pin member is forcedly expanded, stress is not concentrated at one point but distributed over the whole boundary portion welded to form the arcuate cross-sectional shape. This makes it possible to increase the strength of the tape body against the pulling force, so that breakage at the leading end portion thereof can be positively prevented. Further, to effect the welding such that the boundary portion forms the arcuate cross-sectional shape, a horn having a corner whose cross-sectional shape is arcuate is used, so that stress applied to a pin member-side boundary portion of the welded area during the welding is distributed whereby the residual stress at the folded leading end portion can be reduced. This makes it possible to increase the strength against the pulling force, so that breakage of the leader tape body can be positively prevented.
More preferably, the arcuate shape has a radius not smaller than 0.3 mm and not larger than 1.0 mm.
According to this preferred embodiment, the arcuate shape has a radius not smaller than 0.3 mm and not larger than 1.0 mm. Therefore, it is possible to positively prevent breakage of the leader tape body due to the pulling force, while preventing the pin member from falling off.
To attain the above object, according to a third aspect of the invention, there is provided a leader tape including a leader tape body having one end fixed to a tape, for enabling the tape to be pulled out of a cartridge body, and a pin member attached to the leader tape body, for pulling out the tape therewith, the leader tape body having a portion thereof on a side of another end opposite to the one end, the portion being folded such that the folded portion surrounds a periphery of the pin member and that the folded portion has a leading end portion thereof welded to a tape surface of the leader tape body opposed to the folded portion, wherein welding of the leader tape body is effected such that at least one of a pin member-side boundary of a welded area where the folded leading end portion and the tape surface opposed thereto are welded to each other and a one end-side boundary of the welded area forms a protruded shape having a central portion thereof protruded toward the pin member or a recessed shape having a central portion thereof recessed in a direction away from the pin member.
According to this leader tape, welding of the leader tape body is effected such that at least one of the pin member-side boundary of the welded area where the leading end portion and the tape surface opposed thereto are welded to each other and the one end-side boundary of the welded area forms a protruded shape having a central portion thereof protruded toward the pin member or a recessed shape having a central portion thereof recessed in a direction away from the pin member. Therefore, the force applied when the leader tape body is pulled can be distributed over a wider area due to the increased length of the boundary line than when the boundary or boundaries of the welded area are each in the form of a straight line perpendicular to the direction of the length of the tape. This makes it possible to fully prevent the breakage of the leader tape body due to the pulling force. Further, if a welding tool, such as an ultrasonic horn, is used for performing the welding such that the boundary line forms a protruded or recessed shape, the welding tool can be configured to have a simple shape while preserving the effects of prevention of breakage of the leader tape body.
To attain the above object, according to a fourth aspect of the invention, there is provided a tape cartridge comprising a cartridge body, a tape, a leader tape fixedly attached to the tape, the leader tape including a leader tape body having one end fixed to the tape, for enabling the tape to be pulled out of a cartridge body, and a pin member attached to the leader tape body, for pulling out the tape therewith, the leader tape body having a portion thereof on a side of another end opposite to the one end, the portion being folded such that the folded portion surrounds a periphery of the pin member and that the folded portion has a leading end portion thereof welded to a tape surface of the leader tape body opposed to the folded portion, welding being effected non-densely in at least one of a pin member-side boundary portion of a welded area where the folded leading end portion and the tape surface opposed thereto are welded to each other and a one end-side boundary portion of the welded area, and a reel received in the cartridge body, with the tape having the leader tape fixedly attached thereto being wound therearound.
To attain the above object, according to a fifth aspect of the invention, there is provided a tape cartridge comprising a cartridge body, a tape, a leader tape fixedly attached to the tape, the leader tape including a leader tape body having one end fixed to the tape, for enabling the tape to be pulled out of a cartridge body, and a pin member attached to the leader tape body, for pulling out the tape therewith, the leader tape body having a portion thereof on a side of another end opposite to the one end, the portion being folded such that the folded portion surrounds a periphery of the pin member and that the folded portion has a leading end portion thereof welded to a tape surface of the leader tape body opposed to the folded portion, welding of the folded leading end portion being effected such that at least one of a pin member-side boundary portion of a welded area where the folded leading end portion and the tape surface opposed thereto are welded to each other and a one end-side boundary portion of the welded area forms an arcuate shape in cross-section along a tape length, the arcuate shape protruding toward the tape surface opposed thereto, and a reel received in the cartridge body, with the tape having the leader tape fixedly attached thereto being wound therearound.
To attain the above object, according to a sixth aspect of the invention, there is provided a tape cartridge comprising a cartridge body, a tape, a leader tape fixedly attached to the tape, the leader tape including a leader tape body having one end fixed to the tape, for enabling the tape to be pulled out of a cartridge body, and a pin member attached to the leader tape body, for pulling out the tape therewith, the leader tape body having a portion thereof on a side of another end opposite to the one end, the portion being folded such that the folded portion surrounds a periphery of the pin member and that the folded portion has a leading end portion thereof welded to a tape surface of the leader tape body opposed to the folded portion, welding of the leader tape body being effected such that at least one of a pin member-side boundary of a welded area where the folded leading end portion and the tape surface opposed thereto are welded to each other and a one end-side boundary of the welded area forms a protruded shape having a central portion thereof protruded toward the pin member or a recessed shape having a central portion thereof recessed in a direction away from the pin member, and a reel received in the cartridge body, with the tape having the leader tape fixedly attached thereto being wound therearound.
According to these tape cartridges, the force applied to the leader tape body when the leader tape is pulled can be distributed over a wide range of area, such as the whole area of the boundary portion(s). Therefore, it is possible to fully prevent the breakage of the leader tape body due to the pulling force. This improves the durability of the tape cartridge.
It should be noted that the disclosure of the present specification relates to the subjects included in Japanese Patent Application No. 2001-128518 which was filed with Japanese Patent Office on Apr. 26, 2001, and all of the disclosures thereby are expressly incorporated herein by reference.